Field of the Invention
This invention relates to a technology for detecting objects in a vicinity of a vehicle.
Description of the Background Art
Conventionally, an object detection apparatus that detects an object by using captured images acquired by a camera for capturing images of a vicinity of a vehicle is used. The object detection apparatus detects the object based on the captured images, for example, captured by a front camera. By informing a user (mainly driver) of a detection result of the object detection apparatus, the user can easily understand an other vehicle and/or another object approaching from a position that is a blind spot at an intersection having poor visibility, in a parking lot, etc.
One of well-known object detection methods used for such an object detection apparatus is an optical flow method. In the optical flow method, feature points are extracted from captured images (frames) acquired periodically and optical flows that are vectors representing movement of the feature points in the captured images are derived. Then, based on the optical flow, the object in the vicinity of a host vehicle is detected.
In a case where the optical flow method is used, while the host vehicle is traveling, optical flows are derived not only for an object in motion but also for a subject that is a background object. The optical flows relating to such a subject that is a background object may be a cause of false detection of an object.
In conventional object detection apparatuses, object detection sensitivity is set in a predetermined level to avoid such false detection. Therefore, it is difficult to improve object detection performance of the object detection apparatuses.